Sudden cardiac arrest (colloquially “heart attack”) is a frequent cause of death. One treatment for cardiac arrest is quick and competent chest compressions to keep blood flowing through a patient's heart. Along with chest compressions, a rescuer may ventilate the patient by either exhaling into the patient's mouth or nose or utilizing a device that pushes air into the patient's lungs. Rescuers, in particular untrained rescuers, may experience a rush of excitement during such medical emergencies that can result in over-ventilating the patient. Such untrained rescuers may consider such additional ventilations as being helpful to the patient; however, studies have shown the opposite. Additional cycles of inflating and deflating the patient's lungs may raise pressure in the patient's chest causing circulation of the patient's blood to actually decrease. As a result, the ability to monitor ventilations and provide CPR in a competent manner can be a very important personal skill, and is particularly important for professional healthcare workers such as emergency medical technicians (EMTs).